1. Field of the Invention
The present invention relates to a semiconductor storage device such as a DRAM.
2. Description of the Related Art
Recently, a low-power-consumption embedded DRAM provided for mobile applications is of increasing importance, and various embedded DRAMs have been developed as a method for reducing standby power consumption. As one of the methods, the low power consumption is realized by improving data retention characteristics (hereinafter referred to as “retention characteristics”) in a standby state. For example, there has been proposed a method in which a substrate potential of a cell transistor is changed in a standby state to thereby improve the retention characteristics (Patent Document 1: Japanese Patent Application Laid-Open No. 10-289578)
However, since mobile applications now require a lot of complex processing, standby power consumption should be further reduced.